M&P 15-22 FTE issues w/ subsonic ammo and suppressor

[Hoyle]

Bought a brand new M&P 15-22 a couple weeks ago and finally got some time yesterday to test it out. Here's what I'm working with:

M&P 15-22 - Product: M&P(R)15-22 SPORT™ MOE SL(R)
SilencerCo thread spacer - 1/2x28 Rifle Thread Spacer – Silencerco Accessories and Merchandise
AAC Element2 suppressor - ELEMENT2™
Eley Target ammo - Eley 22LR Target ELEY3190 40 gr LRN 50 per box


It fails to eject every 5 or so rounds, and then it'll run smooth for a magazine. Then go back to every 5 or so - very frustrating.

Any help is appreciated.

 

[little_airwolf]

Did you clean everything?
Sounds like the bolt is having issues.
Any marks on spent cases?
How are you loading the mags?
They need to be stacked right.

 

[RedNeck Jim]

When you removed the flash hider, did you clamp the barrel or the upper?

 

[Hoyle]

When you removed the flash hider, did you clamp the barrel or the upper?

Yes I did. I know the importance of properly clamping, especially when the whole rifle is polymer.

 

[Hoyle]

Did you clean everything?
Sounds like the bolt is having issues.
Any marks on spent cases?
How are you loading the mags?
They need to be stacked right.

Quick lube after pulling it out of the box.
Spent cases are being smashed/flatted by the bolt.
Pulling down on the mag follower and loading each round one by one.
How do they need to be stacked?

 

[RedNeck Jim]

How do they need to be stacked?

I think he meant staggered.

My suppressed 15-22s shoot mainly CCI Subsonic, CCI Standard Velocity & Norma Tac-22 with no issues.